Feed-regulator for grinding-machines.



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FEED-REGULATOR FOR GRIN DIN (Fr-MACHINES.-

Specification of Letters Patent.

Patented Dec. 10, 1907.

Application filed Jauary 13. 1903. Serial No. 138.812.

To all whom 'it 'may concern:

Be it known that I, THOMAS A. EDISON, a citizen of the United States,residing at Llewellyn Park, Orange, Essex county, New Jersey, haveinvented a certain new and useful Improvement in Feed-Regulators forGrinding-Machines, of which the following is a specification.

In the operation of grinding machines for the fine grinding of materialin bulk, like Portland cement or cement mixtures, I prefer to supplythe` material to the grinding apparatus by means of a roller feed,although a feeding worm or screw or other mechanism for the purpose maybe employed. In practice, foreign substances, like bolts, nuts, nails,and even wrenches, become accidentally mixed with the material to beground, and are fed to the grinding rolls. The presence of thesehard-foreign substances in the material to be round makes it desirableto drive the grinding rolls through a coupling equipped withshear-bolts, as is common, so

that when a foreign substance reaches the rolls, the increasedresistance results in a shearing of the bolts, thus permitting thegrinding rolls to stop. I find in practice that it is desirable toprovide the feed mechanism for the grinding rolls with a separatedriving motor, the speed of which can be regulated so that the quantityof material supplied to the rolls can be adjusted independently of thelatter. When such a separately driven feed mechanism is employed,.

it becomes highly important that the feed of material should be arrestedwhen the coupling between the grinding rolls and its drivmg enginebecomes sheared and the rolls stop, because otherwise a mass' ofmaterial would be fed to the grinding rolls and would accumulatetherein, increasing the difficulties incident to the removal of theforeign substance.

The purpose of the present invention, therefore, is to provide means bywhich a separately operated feed mechanism will be automatically.arrested when the grinding rolls are stopped from any cause, as, forexample, by the shearing of the driving coupling therefor due to thepresence of any hard foreign substance tending to pass between therolls.

In the drawings which. accompany this specification, Figure 1 shows diarammatically the preferred arrangement of means for that the boltsthereof will be carryingout the invention. Fig. 2 is a detail sectionalview.

1, 1 represent the grinding rolls, of any suitable type, one of thembeing driven by a belt-wheel 2 and the other rotating frictionally. Ashearing coupling of any suitable type is interposed between the drivingmechanism and the driven roll, and arranged so sheared when the load onthe rolls is greatly increased. This .feature is shown in Fig. 2.wherein Sis a circular plate keyed to the driving'shaft and connectedto the flange 3 of the roll 1 by bolts 3b. A hopper 4 is supplied withmaterial, and is provided with a roller or other feed 5 at its bottom,by means of which material will be fed to the grinding rolls.

The feed mechanism is' operated by a Inotor 6 of any suitable t e, anelectric motor being. shown. This e ectrio kmotor is illustrated asbeing connected in a circuit 7 across' the mains 8, 8, an ordinaryrheostat or starting box 9 being included inthe circuit for regulatinthe speed of the motor. The circuit 7 inc udes the contacts .10, 10arranged to be normally closed by a bridging contact 11 'carried on alever 12 which is shown as centrally pivoted. This lever is o erated bya centrifugal governor 13 rotate by a belt 14, .driven by one of thegrinding rolls 1. In consequence, it will be understood' that when theshearing coupling operates to ermit of the sto page of the grinding'rols 1, the governor, llialls will be moved mwards, operating the lever 12,and breakin the circuit 7 so as to stop the motor. vhen the grindinrolls are again started, the governor ba s will be moved outwardscentrifugally, closing the circuit 7 between the contacts 10,' andpermitting the motor to be again started and its speed controlled bymeans of the rheostat 9.

Having indicated the referred way in which my invention may e carriedinto efthe desired result by analogous means will be obvious to thoseskilled in the art.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is as follows z* 1. In grinding apparatus, thecombination with grinding rolls and means including a motor for' drivingthe same, of feed mechanism for supplying material to said rolls, a

feet, many other arrangements for securing separate motor for operatingthe feed mechanism, and means controlled by one of the grinding rollsfor automatically stopping the last named motor when rotation of thegrinding rolls is arrested, substantially as and for the purposes setforth.

2. In grinding apparatus, the combination with grinding rolls, a drivingshaft, means including a motor for driving said shaft and a shearingconnection between the driving shaft and grinding rolls, of feedmechanism for supplying material to the grinding rolls, a separate motorfor operating the feed mechanism, and means controlled by one of thegrinding rolls for automatically stopping the last named motor whenrotation of the grinding rolls is arrested, substantially as and for thepurposes set forth.

3. In grinding apparatus, the combination with grinding rolls, and meansincluding a motor for driving the same, of feed mechanism for supplyingmaterial to said rolls, a separate motor for operating the feedingdevice, means for controlling the speed of the motor, and meanscontrolled by one of the grinding rolls for automatically stopping thelast named motor when rotation of the grinding rolls is arrested,substantially as and for the purposes set forth.

y 4. In grinding apparatus, the combination with grinding rolls andmeans for driving the same, of feed mechanism for supplying material tothe rolls, an electric motor for operating the feeding deviceindependently of the rolls, and means connected with said grinding rollsfor automatically breaking the circuit to said motor when rotation ofthe grinding rolls is arrested, substantially as and forthe purposes setforth.

5. In grinding apparatus, the combination with grinding rolls and meansfor driving the same, of feed mechanism for supplying material to therolls, an electric motor for operating the feeding device independentlyof the rolls, and a centrifugal governor connected with said grindingrolls'for automatically breaking the circult to said motor when rotationof the grinding rolls is arrestd, lubstantially as and for the purposesset ort 6. In grinding apparatus, the combination with grinding rollsand means for driving the same, of feed mechanism for supplying materialto the rolls, an'electric motor for operating the feeding deviceindependently of the rolls, a rheostat ,for controlling the speed of themotor, and means connected with said grinding rolls for automaticallybreaking the circuit to the motor when rotation of the grinding rolls isarrested, substantially as and for the purposes set forth.

7. In grinding apparatus, the combination with grinding rolls and meansfor driving the same, of feed mechanism for supplying material to therolls, an electric motor for operating the feeding device independentlyof the rolls, a rheostat for controlling the speed of the motor, and acentrifugal governor connected with said grinding rolls forautomatically breaking the circuit to the motor when rotation of thegrinding rolls-is arrested, substantially as and for the purposes setforth.

8. In grinding a paratus, the combination with grinding rol s and meansincluding a motor for driving the same, of feed mechanism for supplyingmaterial to the rolls, a separate motor for operating the feedmechanism,.and means connected with said grinding rolls forautomatically stopping the last named motor When rotatlon of thegrinding rolls is arrested, substantially as set forth.

9. In grinding apparatus, the combination with ygrinding rolls, adriving shaft, means including a motor for driving said shaft and ashearing connection between the driving shaft and grinding rolls, ofmeans for supplying material to the grinding rolls, a separate motor foroperating the feed mechanism, and means connected with said grindingrolls for automatically stopping the last named motor when rotation ofthe grinding rolls is a1*- rested, substantially as set forth.

This specification signed and witnessed this 18th day of Dec. 1902.

THOMAS A. EDISON.

